1. The substrate itself is difficult to bond, such as PP, PE, etc. Because of their high molecular crystallinity and low surface tension, they can not form molecular chain diffusion and entanglement with most substances, so they can not form strong adhesion at the interface.

2. The bonding range of the product is narrow, which can only act on some base materials.

3. Insufficient curing time

Generally, the two-component silicone structural sealant shall be cured for at least 3 days after use, and the single component shall be cured for 7 days. If the temperature and humidity of the curing environment are low, it is necessary to extend the curing time.

4 . A. Component B proportion error

When using two-component products, users must strictly follow the ratio of base rubber and vulcanizing agent required by the manufacturer, otherwise problems may occur during early vulcanization, or problems of adhesion, weather resistance and durability may occur during use, and later use.

5. The substrate is not cleaned as required

Since the dust, dirt and impurities on the surface of the substrate will hinder the bonding, it must be strictly cleaned before use to ensure the good bonding between the silicone structural sealant and the substrate.

6. Failure to apply primer as required

Pretreatment with primer on the surface of aluminum profile can shorten the bonding time and improve the water resistance and durability of bonding. Therefore, in practical engineering application, the primer must be used correctly to strictly avoid degumming caused by improper use.